THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE II. VOL. III. 



No. VII.— JULY, 1876. 



oi^iG-iisr-A-Xi J^I^TIOXiSS. 



I. — The Careara Marbles. A Chapter in the History of 

 Continental Geology. 



By G. A. Lebour, F.G.S., London and Belgium, F.E.G.S., etc.; 



Lecturer in Geological Surveying in the University of Durham College of Physical 



Science, JSTewcastle-on-Tyne. 



THE celebrated statuary marbles of Carrara, which have of late 

 years been universally described as of Jurassic age, have quite 

 recently been shown conclusively to belong to the Carboniferous 

 series, and the steps which have led to the discovery form an in- 

 structive illustration of the difficulties which beset Alj^ine Geology. 

 No one lias a better right to relate the history of the classification of 

 the rocks of the Apuan Alps than M. Coquand, and this he is now 

 doing in a series of papers published in the Bulletin of the Geological 

 Society of France. From the first of these we arrive at the following 

 resume of the various opinions which have been held from time to 

 time regarding the age of the statuary marbles.^ 



In 1829 it seems that Paolo Savi believed the Carrara marbles to 

 be of igneous origin, but I cannot find that he anywhere published 

 that opinion. At any rate, in 1833 he referred them to the Cre- 

 taceous series," to which, however, he also referred all the other 

 rocks of the district, including the Verrucano, metamorphic schists, 

 and gneiss. 



In 184:2 came the discovery of characteristic Liassic Ammonites 

 among these beds, and the recognition, by Prof. Savi and every one 

 else, of the horizon yielding them (the well-known " Calcare rosso 

 ammonitifero'') as belonging to the Middle Lias. The bearings of 

 this important find were discussed by M. Coquand in 1845,^ when 

 he showed that the Ammonite bed lay unconformably over the 

 statuary marbles, from which they were separated by a thick con- 

 glomerate, and that the marbles themselves were unconformable 

 to the crystalline schists beneath them. His conclusions were 

 by no means generally accepted. Pilla had in ISM published 

 a sketch of the comparative geology of Italy,* which was afterwards 



1 H, Coquand, " Histoire des Terrains stratifies de 1' Italic centrale se referant aux 

 periodes primaire, paleozo'ique, triasique, rhetienne et jurassique," Bull, Soc. Geo- 

 logique de France, 3® ser. torn. iii. p. '27 (1875). 



^ In a paper published in the " Nuovo Giornale dei Litterati," t. xxvii. (1833 ?). 



3 " Sur les terrains stratifies de la Toscane," Bull. Soc. Geol. France, 2<5 ser. 

 t. ii. p. 155 (1844-45). * Atti Scienz. Ital. p. 568 (1844). 



DECADE II.— VOL. III. — NO. VII. 19 



